Tropical Storm GREG

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TROPICAL STORM GREG DISCUSSION NUMBER 13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2 AM PDT SUN AUG 14 2005
A 14/0447Z TRMM OVERPASS HAS HELPED IMMENSELY IN LOCATING THE
EXPOSED CIRCULATION CENTER. THE TRMM IMAGE AND A 14/0123Z QUIKSCAT
PASS SUPPORT THE INITIAL MOTION. THE QUIKSCAT DATA WAS ALSO USED
TO ADJUST THE WIND RADII. MODERATE NORTHEASTERLY SHEAR CONTINUES
TO HINDER DEVELOPMENT...BUT THE DYNAMICAL MODELS SUGGEST THAT THE
SHEAR WILL WEAKEN AND SHIFT SOUTHEAST. DVORAK CLASSIFICATIONS HAVE
NOT CHANGED FROM THE PREVIOUS PACKAGE...THEREFORE THE INITIAL
INTENSITY WILL REMAIN AT 40 KT. THE GFDL BRINGS GREG TO HURRICANE
STRENGTH IN 24 HOURS...HOWEVER...EARLIER GFDL RUN INTENSITY
VERIFICATION INDICATES A HIGH BIAS IN THE MODEL. THE INTENSITY
FORECAST AGAIN WILL BE BASED OFF OF THE SHIPS AND FSU SUPERENSEMBLE
MODELS...FOLLOWING THE PREVIOUS PACKAGE.
THE INITIAL MOTION IS 245/5. TROPICAL STORM GREG SHOULD CONTINUE ON
A GENERALLY WEST-SOUTHWESTWARD TRACK WITHIN THE BUILDING MID-LEVEL
RIDGE EXTENDING WESTWARD FROM CENTRAL MEXICO. THE GFS AND THE
CANADIAN ARE SOUTHERN OUTLIERS...ERRONEOUSLY MERGING GREG WITH A
TROPICAL WAVE WELL TO THE EAST. THE ECMWF SUGGESTS A VERY STRONG
RIDGE...DRIVING THE TROPICAL CYCLONE QUICKLY TO THE SOUTHWEST
BEFORE TURNING THE SYSTEM SHARPLY INTO THE RIDGE TO THE NORTH LATE
IN THE PERIOD. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS
ADVISORY AND IS BASED ON A NOGAPS...GFDL AND UKMET BLEND.
FORECASTER ROBERTS/KNABB
FORECAST POSITIONS AND MAX WINDS
INITIAL 14/0900Z 15.2N 116.1W 40 KT
12HR VT 14/1800Z 15.0N 116.8W 45 KT
24HR VT 15/0600Z 14.6N 118.0W 45 KT
36HR VT 15/1800Z 14.3N 119.2W 50 KT
48HR VT 16/0600Z 14.3N 120.9W 55 KT
72HR VT 17/0600Z 14.1N 124.0W 60 KT
96HR VT 18/0600Z 14.0N 127.0W 65 KT
120HR VT 19/0600Z 14.0N 130.0W 65 KT
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